With increasing development of science and technology, a variety of electronic devices with communication functions have been introduced into the market. According to the communication forms, electronic devices are classified into wired electronic devices and wireless electronic devices. According to the usage forms, electronic devices are classified into fixed electronic devices and portable (mobile) electronic devices. The portable electronic device (e.g., a tablet computer) has slim appearance similar to the exterior shape of a LCD screen. Consequently, the portable electronic device can be carried easily. Moreover, the screen of the portable electronic device is a touch screen. Through the touch screen, the user may input a command into the portable electronic device to control the operations of the portable electronic device. Generally, when the user intends to input a character or a symbol into the portable electronic device, an on-screen keyboard is enabled and shown on the touch screen of the portable electronic device. The on-screen keyboard is a virtual keyboard simulating the real keyboard device. By touching an icon of the on-screen keyboard, a corresponding character or symbol is inputted into the portable electronic device. In other words, characters or symbols may be directly inputted into the portable electronic device through the on-screen keyboard without the need of using any external keyboard device.
The portable electronic devices that are slim and easily carried have been widely used in daily lives. For example, these portable electronic devices include but are not limited to tablet computers, mobile phones, smart phones, intercoms, notebook computers, navigators and mobile point-of-sale devices.
As mentioned above, the portable electronic device is equipped with the touch screen. However, if the touch screen is damaged, the operations of the portable electronic device fail to be normally handled. That is, it is very important to impart protectiveness to the touch screen. For protecting a protecting function, a protecting case for the portable electronic device is introduced into the market.
Moreover, it is necessary to provide a wireless transmission function to the electronic device. Consequently, an antenna is installed within the electronic device to provide the wireless transmission function such as WLAN, WWAN or GPS. Since many kinds of electronic components are disposed within the electronic device, these electronic components may interfere the antenna and adversely affect the performance of the antenna. Consequently, in addition to the protecting function, it is important to increase the operation efficiency of the antenna of the electronic device.